'ascomycetes' originates from New Latin 'Ascomycetes', ultimately from Greek, specifically the words 'askos' and 'mykes', where 'askos' meant 'sac' and 'mykes' meant 'fungus'.

'ascomycetes' changed from the Greek elements 'askos' + 'mykes' through New Latin 'Ascomycetes' and eventually became the modern English term 'ascomycetes'.

Initially, it meant 'sac-fungus' (a fungus bearing a sac-like spore container), and this original sense has been retained as the term came to denote members of the phylum Ascomycota (sac fungi).